17 2. Mapping Versus Transformation in MDADB Field : Model Management Project [P.Bernstein, MS Research ]«We define a mapping to be a set of mapping elements, each of which indicates that certain elements of schema S1 are mapped to certain elements in S2.« ...transformation between models, requires an explicit representation of mappings, which describe how two models are related to each other ».Ontology Field : OntoMerge Project [D.McDermott, Yale Univ]«It's important to distinguish ontology translation from ontology mapping, which is the process of finding correspondence (mappings) between the concepts of two ontologies. If two concepts correspond, they mean the same thing, or closely related things.17

33 -lessons from the past 5 . Conclusion & PerspectivesModel Driven Architecture allows the development of services by describing their technology-independent and technology- specific aspects in separate models.EDOC (CCA) is closer to WSDL than the UML metamodel and seems more suitable for the modeling of internet applications implemented on Web Services Platforms.« MDA could be the best answer for the development of future Internet Applications on Web Services Platforms »-lessons from the past« There are no (lasting) one-fits-all technology solutions,and therefore technologies will always differ and evolve »[OMG 05]33

34 MDA and Ubiquitous computing(Weiser Vision 1991)Ubiquitous Computing:Weiser introduced the area of ubiquitous computing (ubicomp) and put forth a vision of people and environments augmented with computational resources that provide information and services when and where desired [Weiser 1991].Ubiquitous Information Systems:The vision, where computers are everywhere and a person interacts (anytime and anywhere) with portable devices that are sensitive and responsive to him, has become a reality nowadays. [Satyanarayanan, 01].34

36 Context aware mobile applications Many different definitions for context“Any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and application themselves” [Dey 2001] Context information are not universal but relativeto some situation (application specific)WeatherHoliday Planning36

37 Context aware mobile applications Context awareness“a system is context-aware if it uses context to provide relevant information and/or services to the user, where relevance depends on the user’s task”. Four main features of CW applications:Contextual sensingContextual adaptationContextual resource discoveryContextual augmentation37

38 Context aware mobile applicationsConceptual Framework for Context aware systems[Badaulf, 07]A separation between detecting and using context is necessary to improve extensibility and reusability of systems. From a collection of different sensors to context aware services38

39 Context aware mobile servicesProvide relevant information/services to users using context informationMore friendly, adapted, and intelligent servicesrestaurant finding servicemuseum guide serviceroad search service (maintained and considering road conditions in a real time )Most promising technology for mobile servicesA context aware service is considered as a smart Web service defined as: "a web service that can understand situational context and can share that context with other services" [Manes, 01]39

45 MDA for context aware mobile servicesContext weaving and transformationsA separation between context information and business logic in individual models,The integration of the context model into the business logic using suitable transformation techniques,The mapping of the contextualized business logic model into a web service platform.Two transformation techniques for context weaving:Model composition (Merging)Parametrized Transformation45

48 Context weaving and transformationParametrized transformation: [Frankel 02]Parametrized Transformations allow a designer to mark in the application model (PIM) the properties that will receive context information. These properties are the context_aware properties.48

49 Conclusion and PerspectivesCOMODE (Context Aware Model Driven Development) advocates Model Driven Development to promote reuse, adaptability and interoperability for context-aware applications development on a service platform.Using model driven development, context models are built as independent pieces of application models and at different abstraction levels then attached by suitable transformation techniques.Parameterized transformation technique allows the binding of context information to a service at a model level, and therefore, allows specifying which behavior should be weaved at execution level.49

51 Motivations (1):Technologies are in constant evolution and Companies are often changing their organisationCompanies have to communicate with external Information Systems (IS) as clients, providers, partners using heterogeneous ISSOA driven by a global methodology, seems the best solution for Companies to :Limit impacts of changes in there IS- Provide interoperability between heterogeneous IS51

52 Motivations (2):Web service appears as the simplest solution to integrate IS;Web services promote interoperability because they are based on XML standards: XML EVERYWHERESo, Web services seem to be the ideal solution for companies, The fitted technical solution used to support SOA.but ...52

53 Problems met with Web services in SOA context Code is monolithic mixing concernsAny change requires re deployment and is time consumingNot a full flexibility and poor adaptabilityHence,SOA Applications are faced to some important limitations concerning their adaptability to Business requirements changes53

54 Aspect Oriented Programming (1)AOP is a paradigm that enables the modularization of crosscutting concerns into single units called aspects;AOP allows to encapsulate the code of aspects into separate module –and then apply the code where it is needed.AOP allows adding new behavior to an application without touching the base source code54

58 Conclusion of this technical research workIn this first approach using AOP, a pragmatic solution for adaptable Web service was developed with server and client adaptabilityHowever,This technical solution is very complex for neophyte and requires to be a specialist : so one alternative would be to abstract technical complexity58

60 Context_Aware MDD & Aspects as a new research direction  Key Points60

61 Key PointsContext modeling allows providing information and situation which intervene in the process of service adaptability.Using model driven development, context models are built as independent pieces of application models and at different abstraction levels then attached by suitable transformation techniques.Services are unaware of their context and the aspects adapt them to the current environment according to the current context.Context-dependant behaviors are extracted into aspects and weaved with the base service during execution.Parameterized transformation techniques allow binding context information to a service at a model level, and should help to determine which aspect should be weaved at execution level.61

63 ConclusionWe are convinced MDD is the fitted solution to abstract the complexity of our aspect based solution.We have to clarify and formalize the process of « Aspect derivation » from a given context model.We have to take into account dynamic models, weaving and composition.We have to define models transformations and the fitted plate form to support our approach.63

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